Fire questions I see if I can help. Depends on your system but probably need to cut in a motorised valve controlled through a room thermostat in your conservatory.
Again dependant on your boiler position and pipe runs there would be two options, heating on in house then conservatory avail and the trickier option of conservatory on independant of house. Combi or system boiler in your house?
Would a cheaper option not be heated elements under the tiles? Although when either breaks your pretty much gubbed. What size on conservatory?

I have a combi (new 2 years ago). Conservatory will be 5.4m x 3.8m. The installer is me (jack of all......). My plan is to use a 'one zone pack' where you get the pump and blending valve etc. I was wondering how it worked but think I've sussed it. Does the UFH pump only run when the water in the central heating is above a certain temp AND the conservatory room stat is calling for it? I need to contact the boiler manufacturer to check it will work with another pump in the system. I just don't fancy fitting the electric stuff, not that electrics scare me, I was a spark for 10 years from leaving school. I've read that you have to be careful what you place on the floor i.e. thick rugs, bean bags etc are a no no due to thermal blocking with the electric heating?

I do not like underfloor heating. I fitted it in schools many years ago. Heating would be set to come on 90mins before school opened, it had to warm up the concrete floor. 9.00am, in come 30 children, within 30 mins classroom windows would be wide open because of lack of control of room temp. I see the same thing happening in a greenhouse when the sun comes out. Skirting heating seems a better idea.

I have a combi (new 2 years ago). Conservatory will be 5.4m x 3.8m. The installer is me (jack of all......). My plan is to use a 'one zone pack' where you get the pump and blending valve etc. I was wondering how it worked but think I've sussed it. Does the UFH pump only run when the water in the central heating is above a certain temp AND the conservatory room stat is calling for it? I need to contact the boiler manufacturer to check it will work with another pump in the system. I just don't fancy fitting the electric stuff, not that electrics scare me, I was a spark for 10 years from leaving school. I've read that you have to be careful what you place on the floor i.e. thick rugs, bean bags etc are a no no due to thermal blocking with the electric heating?

Cheers

No need for two pumps,just add the pipework (in one continuous length,NO joints) as though you were adding a radiator (which is the continuous pipe),the thermostat for the pipework sits on the lower part of a wall as it exits your conservatory and hooks up with the rest of the CH system.

I installed a system as above in a kitchen extension I built six yrs ago,the boiler is a combi,and the heated floor is in the screed with ceramic tiling on top.
Works like a dream,toasty toes

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Never argue with an idiot on the internet. He will drag you down to his level and beat you with experience.

No need for two pumps,just add the pipework (in one continuous length,NO joints) as though you were adding a radiator (which is the continuous pipe),the thermostat for the pipework sits on the lower part of a wall as it exits your conservatory and hooks up with the rest of the CH system.

I installed a system as above in a kitchen extension I built six yrs ago,the boiler is a combi,and the heated floor is in the screed with ceramic tiling on top.
Works like a dream,toasty toes

Only problem here is there is no control, heating on in conservatory will only be regulated by house room stat. I'd fit motorised valve on the circuit branched from the original and fit another stat in conservatory. So on a sunny day you can have heating on in house but conservatory switched off and soaking up the suns rays through the glass.

Buy a zone valve and roomstat and throw the heating pack away. Where and why do you have a blending valve? No need as that would cool water..

Only problem here is there is no control, heating on in conservatory will only be regulated by house room stat. I'd fit motorised valve on the circuit branched from the original and fit another stat in conservatory. So on a sunny day you can have heating on in house but conservatory switched off and soaking up the suns rays through the glass.

Buy a zone valve and roomstat and throw the heating pack away. Where and why do you have a blending valve? No need as that would cool water..

You missed the thermostat that controls the heated floor,this thermostat is a separate stat to the one that controls the rest of the rads in the house.
The heated floor in my kitchen is controllably separately.

"the thermostat for the pipework sits on the lower part of a wall as it exits your conservatory and hooks up with the rest of the CH system".

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Never argue with an idiot on the internet. He will drag you down to his level and beat you with experience.

Only problem here is there is no control, heating on in conservatory will only be regulated by house room stat. I'd fit motorised valve on the circuit branched from the original and fit another stat in conservatory. So on a sunny day you can have heating on in house but conservatory switched off and soaking up the suns rays through the glass.

Buy a zone valve and roomstat and throw the heating pack away. Where and why do you have a blending valve? No need as that would cool water..

I wasn't sure if I could do this or not. I didn't know if the UFH needed a pump and manifold. If I can just run it from an MOV teed into the existing CH controlled via a room stat in the conservatory then that's all good. Will the boiler cope with the extra load though? This is an example of what I was looking at: http://www.ebay.co.uk/itm/Underfloor...item5adf6d3aaa

Just think of the UFH as installing a new rad,coupled to either a TRV or coupled to a separate stat.

You're over complicating a very simple addition to your existing system.

In terms of your existing boilers capacity,and whether it will cope,check the KW/BTU output of your boiler.
Find a calculator online that will work out the extra capacity of the UFH,and do a comparison against the extra load of the UFH on the Combi.

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Never argue with an idiot on the internet. He will drag you down to his level and beat you with experience.

Just think of the UFH as installing a new rad,coupled to either a TRV or coupled to a separate stat.

You're over complicating a very simple addition to your existing system.

In terms of your existing boilers capacity,and whether it will cope,check the KW/BTU output of your boiler.
Find a calculator online that will work out the extra capacity of the UFH,and do a comparison against the extra load of the UFH on the Combi.

Perfect, thanks for that. I'll have a look at the boiler and do as you said. This job's getting a whole lot cheaper

More importantly,is the floor going to be a solid one (DPM/Concrete/insulation/screed/tile) or a hung timber floor?

I'm guessing solid?

It's block-cavity-brick and the floor will be timber joists, insulated inbetween with an 18mm chipboard deck sat on the top, UFH to be installed on top of the deck and a lam. floor on top of that. I have taken down an old conservatory which had a tiled floor on a concrete slab, this is 8" lower than my existing floor in the house and I'm bringing it up to level so using joists is easiest plus I still need to vent under the floor of the existing house which I can easily do using this route.

It's block-cavity-brick and the floor will be timber joists, insulated inbetween with an 18mm chipboard deck sat on the top, UFH to be installed on top of the deck and a lam. floor on top of that. I have taken down an old conservatory which had a tiled floor on a concrete slab, this is 8" lower than my existing floor in the house and I'm bringing it up to level so using joists is easiest plus I still need to vent under the floor of the existing house which I can easily do using this route.

Sounds good,although my system is under a screed with ceramic tiles sitting on top.

I used Hepworth, who when I installed the system provided a kit comprising the required (based on floor area) single length pipework,the fittings + the stat.

It's block-cavity-brick and the floor will be timber joists, insulated inbetween with an 18mm chipboard deck sat on the top, UFH to be installed on top of the deck and a lam. floor on top of that. I have taken down an old conservatory which had a tiled floor on a concrete slab, this is 8" lower than my existing floor in the house and I'm bringing it up to level so using joists is easiest plus I still need to vent under the floor of the existing house which I can easily do using this route.

Expensive route and not as good as a screed!

You will need to lay a concrete oversite then the bottom of joists need to be 125mm clear of that!